The present disclosure generally relates to systems and methods for prediction of gas turbine trips due to component failures such as thermocouple failures.
Gas Turbines are the main power producing components for combined cycle/independent power plants. A mixture of air and fuel is burnt in the combustor to produce thermal/heat that is converted into mechanical energy in the several stages of the turbine. Since the firing temperature of the combustor is very high (in the range of 1300-2200° F. (704-1204° C.)), the state of the combustor is measured by mounting thermocouples (TC) in the turbine exhaust. A dedicated controller assesses the state of the combustion process from these thermocouples and further determines if there are any abnormal operations in the combustor. If there is any abnormal event, it warrants immediate shut down of the combustor, hence the gas turbine. For example, exhaust TC failures can cause the controller to provide an incorrect indication of an abnormality in the combustion process. Under this situation, the controller cannot determine whether there is a real combustion event or not, and initiates a gas turbine trip, that is, a rapid uncontrolled shutdown of the gas turbine that is initiated by the turbine controller to protect the turbine from failures. In general, there can be several failure modes for a thermocouple such as grain growth in junction, insulation degradation, loose connections, shorting of lead wires, grounding of thermocouple wire, melted thermocouple junction, etc. Operators typically cannot predict trips due to TC failure.
Unwarranted trips, as mentioned above, can cause revenue loss and also have the adverse effect of reducing life of turbine components. Hence, there is a need for predicting an impending trip reliably and preventing loss of useful life of a gas turbine.